Mathematical Modeling of the No-bleed Air Conditioning System for an Advanced Passenger Aircraft
0
Citation
11
Reference
10
Related Paper
Abstract:
At the moment, the most perspective development direction of the aviation industry is the creation of a more electric aircraft and in this case, there are no bleed systems that taking air from the engine, which is necessary to ensure the operation of the air conditioning system and ice protection system. This article discusses the possibility of using no bleed systems and calculating the required characteristics using mathematical modeling. Simulation results show the operation modes of a centrifugal compressor and using to compare two versions of the air-cooling units in case of rotational speed of compressor is limited. The simulation results presented in this article can be used in the design of compressors for advanced electric air conditioning systems.Keywords:
Bleed
Centrifugal compressor
The subject of research was the oil-associated gas high pressure compressor station. Operation of two-cycle centrifugal compressor installation at limit working conditions with using advanced method of gas-dynamic characteristics simulation (recalculation) for other operation conditions has been considered. Considered limit the compressor installation operation modes allowed to prove selection of design pressure for pipelines and equipment.
Centrifugal compressor
Compressor station
Cite
Citations (0)
Wet Gas Compression technology for centrifugal compressors is without doubts one of the topics that have enjoyed a most rapidly growing interest in recent years [1]. This is certainly due to the new opportunities for exploiting aging gas fields, which are rendered possible by this technology. However, despite the numerous recent works on this topic, the fundamental understanding of wet gas compression processes remains challenging in the sense that no unified standards for testing and performance exist, and that the understanding of the basic physical phenomena is not fully complete. The present work is concerned with such issues and contributes experimental results and performance analysis for a low pressure-ratio centrifugal compressor stage in heavily wet gas streams. An open loop test rig was built for a single scale model centrifugal compressor to be run at typical design operating range. The impeller was a standard impeller with no design adjustments for wet streams. The performance was assessed at liquid mass fractions (LMF) ranging between 0% and 50% and at average droplet diameters between 50 μm and 75 μm, as well as non-atomized liquid streams. The results clearly demonstrate that wet gas strongly influences compressor performance, considering adsorbed power, efficiency and compressor characteristics. The results also show that, although the impeller design did not account for heavily wet streams, the overall compression characteristics remain good and the machine was able to process the two-phase mixture without failures, in some cases with improved pumping. The compressor exit temperatures of the gas phase in heavily wet conditions are key to assessing machine performance, in particular efficiency, for wet gas compression. Although an accurate technology approach for measuring such temperatures has not yet been developed, in the present work a droplet model is proposed. This model is then calibrated with experimental data in order to develop a methodology providing reliable efficiency values.
Centrifugal compressor
Overall pressure ratio
Cite
Citations (9)
Abstract Various engineering techniques are used to calculate and design centrifugal compressors, one of which is the Universal Modelling Method developed at SPbPU. Variants’ of centrifugal compressors analysis is the first step in gas-dynamic design. Brief information on the simplified mathematical model of efficiency is presented. It is possible to compare the variants of compressors with different number of shafts, shafts RPM, the number and location of intercoolers, the type of impellers and diffusers. Examples of a variants’ calculation of a pipeline compressors, a compressor for underground gas storage and a general-purpose air compressor are presented. It is shown that single-shaft compressors for underground gas storages should be optimized by selecting the maximum possible number of stages, by selecting the ratio of loading factors and the diameters of the impellers. It is shown that the single-shaft scheme of a general-purpose air compressor is inferior in efficiency to a two-shaft scheme with larger number of intercoolers. The presented samples have demonstrated that computer program based on a simplified mathematical model for industrial centrifugal compressors provides reliable and sufficient information for different compressors variants’ analysis.
Centrifugal compressor
Axial Compressor
Air compressor
Compressor station
Cite
Citations (9)
This study discusses the design features and operational case histories of high pressure, centrifugal gas-injection compressors. These compressors are currently being operated in the Phillips Group-Ekofisk, North Sea Project. High density gas compression can involve a problem called subsynchronous rotor whirl in centrifugal compressors. The methods of attacking and solving this problem are discussed. It is concluded that centrifugal compressors will satisfy any known gas injection requirements.
Centrifugal compressor
Cite
Citations (5)
Centrifugal compressors are critical rotating equipments in industrial processes, especially for natural gas applications. Compressible gas exhibit complex flow behavior that requires a thorough understanding to ensure extended, safe and stabilized compressor performance. Without, Centrifugal compressors can undergo surge which restricts compressor operational range and jeopardize the safety of its components. Dynamic simulation then becomes necessary to evaluate performance and to implement integrated control schemes. This paper will investigate how centrifugal compressor responds to changes at inlet conditions i.e. increase in pressure, temperature and molecular weight. The effect of these changes on compressor performance will be simulated using Unisim Design dynamic compressor model. Results show that compressor operation is easily influenced by changes in inlet condition and that integrated control schemes are effective in safeguarding compressor from surge.
Centrifugal compressor
Reciprocating compressor
Compressor station
Cite
Citations (0)
The work sets out the distinctive features of the method of gas-dynamic calculation of multistage centrifugal compressors for refrigerating machines running on a cycle of multi-stage compression of working fluid with its complete intercooling between the stages. The parameters of width of specific sections of the impellers, diffusers, and reverse guide vanes as well as the operating parameters during polytropic compression and parameters of the inner power of the compressor were corrected. The research outcomes can be used in the design of centrifugal compressors for refrigerating machines operating at the specified cycle.
Centrifugal compressor
Working fluid
Vapor-compression refrigeration
Diffuser (optics)
Cite
Citations (1)
This article discusses centrifugal pumps and compressors that have reached efficiency levels above 90 percent and are built in sizes ranging from a few watts to megawatts. As machines have evolved to handle a wider range of liquids and gases at higher pressures and temperatures, whole industries have become dependent on them. The centrifugal impellers in these pumps and compressors make them among the most complex fluid machines ever built. The development of the centrifugal impeller has been helped because the device can be used in both pumps and compressors. The earliest development occurred in pumps, which were more advanced than compressors until early in the 20th century.
Centrifugal compressor
Cite
Citations (5)
Gas turbine driven centrifugal compressors are widely used in the oil and gas industry. In evaluating the optimum selection of gas turbine drivers for centrifugal compressors, one of the main objectives should be to verify proper integration and matching of the centrifugal compressor to its gas turbine driver. Gas turbines are of standard designs, while centrifugal compressors are specifically designed to meet customer requirements. The purchaser should clearly specify process requirements and define possible operating scenarios for the entire life of the gas turbine driven centrifugal compressor train. Process requirements defined by the purchaser, will be used by the compressor designer to shape the aero-thermodynamic behavior of the compressor and characterize compressor performance. When designing a centrifugal compressor to be driven by a specific gas turbine, other design requirements are automatically introduced to centrifugal compressor design. Off-design performance, optimum power turbine speeds at site conditions as well as optimum power margin required for a future-oriented design must all be considered. Design and off-design performance of the selected gas turbine at site conditions influences the final selection of a properly matched centrifugal compressor design. In order to evaluate different designs and select the most technically viable solution, the purchaser should have a clear understanding of the factors influencing a proper match for a centrifugal compressor and its gas turbine driver. This paper discusses criteria for evaluating the most efficient combination of a centrifugal compressor and its gas turbine driver as an integral package from a purchaser’s viewpoint. It also addresses API standard requirements on gas turbine driven centrifugal compressors.
Centrifugal compressor
Axial Compressor
Cite
Citations (4)
The unsteady behaviour of compressor systems near the surge line and during surge was investigated. Experimental examinations were carried out using a three stage centrifugal compressor of industrial design in different types of piping systems. The results obtained were compared with different theoretical models. It is demonstrated that the compressor system behaviour can be calculated adequately, if sufficient data concerning the transient characteristic of the compressor are available.
Centrifugal compressor
Transient (computer programming)
Axial Compressor
Cite
Citations (1)
Performance monitoring of wet gas compressors is challenging due to the liquid phase impact on performance. Introduction of a liquid phase alters both the thermodynamics as well as the fluid dynamics of the compression process. Hence, understanding the flow interaction between the impeller, diffuser and volute is pivotal. Previous investigations have detected occurrence of compressor hysteresis at certain wet gas operating conditions, resulting in temporary deviations from the steady state compressor characteristics. This kind of behavior influences both the compressor stability and performance. Thus, being able to understand the onset of hysteresis and its impact on the compressor is paramount. An experimental test campaign has been performed at the Norwegian University of Science and Technology (NTNU). The test facility is an open loop configuration consisting of a shrouded centrifugal impeller, a vaneless diffuser and a circular volute. The current investigation document the compressor performance shift and the occurrence of compressor hysteresis when gradually increasing the liquid load on a centrifugal compressor. Emphasis was put on the compressor performance and its correlation to the diffuser multiphase flow regime. The investigation revealed that there is a clear dependence between the diffuser multiphase flow characteristics and the compressor performance.
Centrifugal compressor
Volute
Diffuser (optics)
Axial Compressor
Hysteresis
Cite
Citations (0)